1. Field of the Invention
The present invention pertains to the technical field of ion mobility detection application. Specifically, the present invention relates to pre-concentration technique for detecting drugs, explosives and other substances, which can be employed to pre-concentrate particles of drugs, explosives and other substances floating in air. More specifically, the present invention relates to a pre-concentration device and method for an ion mobility detection apparatus.
2. Description of the Related Art
In the prior arts, gas sample feeding methods used with an IMS instrument for detecting drugs, explosives and other substances primarily include the following two types. According to one type of analysis method, samples are continuously fed and sampled without gas pre-concentration processing. According to another type of the methods, separate gas pre-concentration processing and gas sampling are included.
However, in the analysis method comprising the separate gas pre-concentration processing and gas sampling, on one hand, it is required to provide a larger contact area when collecting substances, such as drugs and explosives, in the air so as to enhance adsorption abilities to absorb substances to be detected; on the other hand, it is required to obtain a higher substance volatilization concentration during detection to improve detection precision of the IMS (Ion Mobility Spectrometer) instrument. Unfortunately, providing a larger contact area during adsorption often causes the volatilization concentration of the substances to be lower during desorption. As a result, detection sensitivities of the IMS instrument are not high.
Further, the gas sampling step has to be implemented after the pre-concentration processing step has been implemented as the separate gas pre-concentration processing and gas sampling steps are employed, and the steps are repeated in this manner. Thus, detection efficiencies of the apparatus will be degraded.